Since 8.3.3 we fail to do the resync when a partial resynch is not
possible, but a full synch is necessary.

This regression was introduced with 7101539930c0a89146959e7a39c09ad9c3516434
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>